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WO1997008598A1 - Procede de detection numerique simultanee sensible aux phases de series de donnees saisies pratiquement en meme temps, resolues dans le temps et faisant partie d'un systeme periodiquement stimule - Google Patents

Procede de detection numerique simultanee sensible aux phases de series de donnees saisies pratiquement en meme temps, resolues dans le temps et faisant partie d'un systeme periodiquement stimule Download PDF

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Publication number
WO1997008598A1
WO1997008598A1 PCT/CH1996/000293 CH9600293W WO9708598A1 WO 1997008598 A1 WO1997008598 A1 WO 1997008598A1 CH 9600293 W CH9600293 W CH 9600293W WO 9708598 A1 WO9708598 A1 WO 9708598A1
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psd
phase
stimulation
array
original data
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PCT/CH1996/000293
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German (de)
English (en)
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Urs Peter Fringeli
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Gff Technopark
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    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B17/00—Systems involving the use of models or simulators of said systems
    • G05B17/02—Systems involving the use of models or simulators of said systems electric

Definitions

  • the present invention relates to a method and its application for the simultaneous, digital phase-sensitive detection of time-resolved, quasi-simultaneous data arrays of a periodically stimulated system according to claim 1, and a device according to claim 16.
  • Phase-sensitive detection is an analytical measurement method that enables the selective and time-resolved detection of the periodic response of a system to a periodic change in external parameters, such as pressure (p), temperature (T), concentration (c), and electric field (E), electrical current density (j), radiation flux density (I) etc.
  • the information content on the dynamics (kinetics) of the stimulated process is in the frequency dependence of the signal amplitudes, as well as the phase shifts of the signals with respect to the external stimulation.
  • the selectivity of the method is given by the fact that only signals with the stimulation frequency ⁇ and their overtones n ⁇ are detected with PSD. All other signals are suppressed.
  • PSD processes have been used in a variety of ways and have been described in various ways (Hs.H. Günthard, Modulation Specroscopy, Ber. Bunsengesellschaft Phys.Chemie, 78, 1110-1115 (1974); Ch. J. Manning and PR Griffiths , Step-Scanning Interferometer with Digital Signal processing, Applied Specroscopy, 47, 1345-1349 (1993)).
  • FFT frequency sensitive detection
  • PSD phase sensitive detection
  • the object of the invention is to acquire and process measurement data arrays simultaneously or quasi-simultaneously, i.e. to proceed with the measurement data arrays as if they were individual measurement points.
  • the measuring time can be considerably shortened without any significant loss of accuracy.
  • the main area of application of the vectorial analysis method according to the invention is in modulation spectroscopy using Fourier transform and diode array spectrometers.
  • Output signal of the PSD during demodulation with the stimulation frequency ⁇ (fundamental tone frequency, index 1).
  • the signal is dependent on the phase shift ⁇ , the fundamental component of S (t) (see FIG. 1A), and on the choice of the phase angle of the PSD, ⁇ PSD _ ,.
  • ⁇ j is the system-related phase angle of the system response with the frequency ⁇ (see also FIG. 2A and modulation spectra).
  • Output signal of the PSD with simultaneous detection with the stimulation frequency ⁇ (fundamental tone frequency, index 1).
  • the signal is dependent on the phase shift ⁇ n of the fundamental component of the i-th data array component of S (t) (see FIG. IB), and on the choice of the phase angle of the PSD, ⁇ PSD> 1 . .phi..sub.i is the system ⁇ related phase angle array of the portion of the system response ⁇ with frequency. It consists of the components ⁇ llr where l ⁇ i ⁇ I (see also Fig. 2B and modulation spectra).
  • Support point array Support point spectra
  • S k Data array assigned to an interval k or coaddition of M data arrays with I components each, where 1 ⁇ k ⁇ N and 1 ⁇ i ⁇ I (see FIG. IB).
  • Period generated mean (see FIG. 2B).
  • the original data array S (t) (FIG. IB) consists of spectra, for example FIG. 5, fundamental and harmonics of the output signals of the PSD, respectively.
  • tion spectra of an FFT as Modula ⁇ refers to the corresponding result (see fundamental, harmonic, ORIGINAL DATA array).
  • Multiparametric stimulation multi-parametric stimulation of the system by simultaneously changing more than one external parameter.
  • the signal is dependent on the difference between the absolute phase shift ⁇ n of S (t) with regard to the stimulation and the phase setting ⁇ PSD, n at the PSD.
  • Output signal array (Fig. IB, item 20), the PSD when stimulated with the fundamental frequency ⁇ and simultaneous demodulation with the n-fold frequency (n ⁇ , (nl) th overtone).
  • the signal is dependent on the difference between the absolute phase shifts ⁇ 1R of the individual data array component S, (t) with regard to the stimulation and the phase setting ⁇ PSD> n on the PSD (see also FIG. 2A and modulation spectra).
  • the original data array consists of I components S, (t), (where 1 ⁇ i ⁇ I), for example the intensities, absorbances or transmittances in the wavenumbers v ,, or. the intensities an interferogram at the corresponding mirror positions of an interferometer.
  • I components S, (t), (where 1 ⁇ i ⁇ I) for example the intensities, absorbances or transmittances in the wavenumbers v ,, or. the intensities an interferogram at the corresponding mirror positions of an interferometer.
  • Each of these components shows a time dependency characteristic of the system.
  • each array component can be described by a Fourier series in the steady state. The corresponding Fourier coefficients are experimentally accessible through a PSD or FFT.
  • Thermodynamic parameters such as pressure p, temperature T, concentration c, electric field E, electric current density j, radiation flux density I, etc.
  • Phase shift of the system response with the frequency n ⁇ with respect to the stimulation Measure of the delay in the system response due to the dynamic properties of the periodically excited system (eg chemical reaction) with respect to the stimulation.
  • Each interpolation point is therefore assigned as many phase angles ⁇ n as there are demodulation frequencies.
  • phase array 1 .22 phase array, phase vector, phase angle array, ⁇ "
  • ⁇ n is composed of components I ⁇ nl and is a measure of the rule by the Dynami ⁇ properties of the excited system periodically (for example chemical reaction) induced delay of the system response.
  • Each interpolation point is therefore assigned as many phase vectors ⁇ n as there are demodulation frequencies. 1 . 23 phase resolution ⁇
  • phase resolution can be refined approximately arbitrarily by interpolation.
  • phase angle of the PSD switching function freely selectable by the experimenter based on the use of external stimulation.
  • n 1 there is the fundamental and for n> 1 the overtones.
  • the corresponding phase angles are, ⁇ PSD; 1 , ⁇ PSD . 2 / ⁇ PSD . 3 '/ ⁇ PSD. ⁇
  • the frequency is limited by the sampling theorem n ⁇ N / 2.
  • sampling time, sampling time, X
  • Time to acquire a data array e.g. of a spectrum.
  • Object e.g. chemical reaction mixture that can be influenced by changing external parameters.
  • thermodynamic equilibrium If a system that is in thermodynamic equilibrium is exposed to a periodic external stimulation, after a settling time t E (see there) it reaches a state that can be described component by component by Fourier series and is called stationary. See system response and Fig. IB, item 20.
  • the data acquisition in modulation experiments should only take place t E time units after switching on the periodic, external stimulation (see stationary state).
  • Theorems must be n ⁇ N / 2. N Number of intervals into which a period is divided
  • FIG. IA Schematic representation of a known method for conventional modulation spectroscopy
  • a one-component measuring device 1 which can be, for example, an FTIR spectrometer or a diode array spectrometer, contains a sample 2 or a system which is to be analyzed.
  • the sample 2 is periodically excited or stimulated via a stimulation and reference unit 3 with the frequency ⁇ , while the demodulation by the PSD at the frequencies ⁇ , 2 ⁇ , ... n ⁇ ,
  • the data acquisition unit 4 thus contains the time course of a one-component signal as a system response to a periodic, external one
  • the system response S (t) is demodulated in accordance with the reference signal S ref .
  • the system is characterized by the amplitudes of the DC term, the fundamental ( ⁇ ), the overtones (2 ⁇ ... n ⁇ ) and the corresponding phase shifts with respect to the excitation ( ⁇ ,, ⁇ 2 , ..., ⁇ n ).
  • the output unit 10 thus are the outputs of the PSD function of the freely chosen on the reference unit phases ⁇ angle ⁇ PSD and the typical system, absolute Phasenverschiebun ⁇ gen ⁇ , (root), ⁇ 2, ..., ⁇ n (overtones) for Grouting.
  • the corresponding components have the following designation: A Q for the DC component, Aj for the fundamental with the frequency ⁇ and A 2 , ..-. , A n for the overtones with the corresponding frequencies 2 ⁇ ..., n ⁇ .
  • IB shows a schematic representation of the method according to the invention for a simultaneous, multicomponent modulation spectroscopy.
  • Sample 2 stimulation and reference unit 3 and line 8 with the reference signal S ref correspond to FIG. 1A.
  • a multicomponent measuring device 11 or array measuring device which can be, for example, an FTIR spectrometer or a diode array spectrometer, contains a sample 2 or a system which is to be analyzed.
  • the sample 2 is periodically excited or stimulated by means of a stimulation and reference unit 3 with the frequency ⁇ .
  • Such periodic stimulation via an external parameter (p, T, c, E, j, I, etc.) triggers periodic reactions in the system.
  • the time profile of a multi-component signal is thus recorded as a system response to a periodic, external stimulation in the stationary state.
  • Each component S x (t) corresponds to a signal according to FIG. 1A.
  • a typical signal curve of the signals S S (t), which are recorded in the data acquisition unit 14, is shown schematically in three dimensions in FIG. 1B.
  • a digital multi-component phase-sensitive detector (PSD) 16 which is connected on the one hand via lines 17 to the data acquisition unit 14 and on the other hand via a line 8 to the stimulation and reference unit 3, the arrays are rectified in a phase-sensitive manner (Lock-m amplifier ), the reference signal S ref being fed to the PSD 16 via the line 8.
  • the digital multi-component phase-sensitive detector (PSD) is used for the simultaneous demodulation of the multi-component system response in accordance with the reference signal S ref , or. of the algorithms described.
  • the multi-component PSD works with entire signal vectors and is therefore more efficient (by a factor of one) in the number of vector components.
  • phase angle ⁇ PSD between the stimulation / reference unit 3 and the phase-sensitive detector 16 is kept constant, a data vector of the time-independent background absorption (DC component) A Q , the fundamental tone, is generated for each operation in the PSD of the signal S (t) A and the overtones A 2 , ..., A "registered.
  • the signals selectively rectified with respect to the frequencies ⁇ , 2 ⁇ ... n ⁇ are fed via lines 19 to an output unit 20, in which they are represented as a function of the phases ⁇ PSD ⁇ n , specifically as signal vectors A Q , A- ( ⁇ j — ⁇ PSD # 1 ), A 2 ( ⁇ 2 - ⁇ PSD 2 ), •
  • the multi-component output signals of the PSD are thus in the output unit 20 as a function of the difference in the freely selectable phase angle ⁇ pso. n and d of the system-typical phase vectors ⁇ n are available.
  • the corresponding output signals are: A Q for the DC components, A, for all fundamental tones (frequency ⁇ ) and A 2 , ..., A ,, for all overtones (frequencies 2 ⁇ ..., n ⁇ ).
  • the harmonic stimulation in which only one frequency is used and which is referred to below as monofrequency stimulation or single frequency stimulation (SFS), and the multifrequency Stimulation or Multiple Frequencies Stimulation (MFS), in which two or more frequencies are included in the excitation waveform. Since the excitation is periodic and can therefore be represented by a Fourier series, the MFS must be the fundamental tone frequency and the corresponding harmonic frequencies.
  • SFS has the advantage of simplicity and clarity ⁇ tion frequency arise, this is a clear indication that nonlinear processes are running in the system, which in turn allows important conclusions to be drawn about the dynamics (kinetics) of the stimulated process.
  • the range of suitable stimulation frequencies is described by equation (2), where ⁇ r min and ⁇ r max mean the shortest and the longest relaxation time of the system.
  • MFS always applies when a periodic function not re ⁇ r is harmonious.
  • the fundamental frequency ⁇ there is at least one frequency (overtone) n ⁇ with n> 2.
  • n there is at least one frequency (overtone) n ⁇ with n> 2.
  • the system responses are delayed in accordance with the characteristic relaxation times ⁇ r raln ⁇ r ⁇ r max by the phase angle ⁇ r and in parallel the corresponding amplitudes are damped.
  • the frequency dependency of both effects depends significantly on the reaction scheme on which the stimulated process is based.
  • MFS can therefore simultaneously provide information about the periodic behavior of a system at several frequencies, which means that the measurement effort involved in elucidating a reaction mechanism can be significantly reduced.
  • the generation of a sinusoidal stimulation waveform can be so complex that a harmonic excitation (see above) is intentionally dispensed with. This inevitably leads to an MFS. In this case it will be necessary to carry out a Fourier analysis of the excitation waveform in order to be able to carry out significant kinetic analyzes.
  • the function (3) results in a simultaneous excitation with the frequencies ⁇ , 3 ⁇ , 5ü), ie with the odd multiples of the
  • This waveform consists of the positive half wave of a sine function.
  • the second half wave (half period) is zero.
  • the Fourier series (4) represents:
  • Non-symmetrical rectangular stimulation broadband stimulation with possible amplitude adjustment
  • curve 26 represents a non-symmetrical rectangular stimulation that is centered in the middle of the period. It is represented by the Fourier series (5).
  • ⁇ (t) ⁇ max ⁇ / ⁇ + 2 / ⁇ ⁇ ⁇ (-l) ⁇ / ⁇ • sin ( ⁇ / ⁇ ) • sin ( ⁇ t) ⁇ (5) ⁇ -l
  • the amplitude pattern of the excitation frequencies can be influenced in a targeted manner by choosing the stimulation duration ⁇ .
  • Example 2.2.2.3 is intended to show that excitation waveforms can be assembled in order to generate certain frequency and amplitude patterns. The analysis of the response of a system to ready-made forms of stimulation can contribute significantly to elucidating the mechanism of the stimulated response.
  • Frg. 2A shows a section of a signal curve of the system response 22 of the i-th component of the data array with harmonic stimulation 21.
  • the reference zero crossing can be recognized at the beginning of the period.
  • the system response 22 here consists of the i-th component of the data array S ⁇ S.ft) with fundamental ( ⁇ ) and 1st overtone (2 ⁇ ) components.
  • the sluggishness of the system in response to the external stimulation leads to phase shifts ⁇ n ( ⁇ ) and ⁇ 12 (2 ⁇ ).
  • this process can be repeated for any number of P periods (1 ⁇ q ⁇ P), with data arrays being averaged during or after the data acquisition over each M within the interval ⁇ t, resulting in the corresponding interpolation point array arises.
  • averaging is generally carried out over P measurement cycles in the steady state (FIG. 2B).
  • the period ⁇ corresponds to the time between two successive sampling or stimulation points.
  • this process can be implemented using a PLL-controlled oscillator, item 52.
  • This control unit receives a signal, item 51, with the frequency ⁇ 0 and generates the N times the frequency Nc ⁇ t ,.
  • C ⁇ b can be, for example, the above-mentioned cosine-shaped interferogram of the monochromatic light source, the zero crossings of which determine the time when the sample is stimulated.
  • the zero crossings of the output signal of the frequency multiplication unit (frequency NC ⁇ f c)
  • the time-resolved data acquisition of the N interferogram points S ki to the respective ith reference points is triggered via a line, item 53, see FIG. 10.
  • the support points are recorded as in section 3.1.2. described.
  • This averaging process can improve the signal / noise ratio by a factor of 1 / "VP.
  • FTIR Fourier transform infrared
  • the system characteristic waves for pay ⁇ indicate the corresponding components of S kl the in Figure 2B behavior shown schematically, but which is still masked by the dominating, non-modulated background 42 (FIG. 6).
  • M 12 spectra were added and assigned to the k-th support point.
  • the numbering (k) of the spectra 27 (FIG. 4) gives the assignment to the corresponding reference points, the 1st and 17th spectrum being identical because of the periodicity of the process.
  • the N support points (arrays) (Fig. 2B) are with a rectangular switching function (6)
  • R (t) 4 / ⁇ ⁇ (i / 2 ⁇ + i) sin [(2 ⁇ + l) ( ⁇ t- ⁇ PSD / 1 )]; 6) ⁇ 0 multiplied.
  • R (t) takes the value +1 during one half-period and -1 during the following half-period. After that, the mean must be formed over a full period.
  • This switching function represents a Fourier series, the result still having to be scaled by the factor ⁇ / 2 in order to ensure a 1: 1 amplitude transmission.
  • ⁇ PSD ⁇ l is the phase setting that can be selected by the experimenter at the reference unit of the PSD.
  • phase resolution .DELTA..phi.
  • the overtones with angular frequencies 2 ⁇ , 3 ⁇ ,, n ⁇ result analogously, the corresponding periods being ⁇ / 2, ⁇ / 3,, ⁇ / n, with n ⁇ N / 2 (sampling theorem).
  • the original data can therefore be evaluated 2, 3, and n times to ensure that
  • the phase resolution is reduced accordingly, unless new interpolation points are approximated.
  • the number of interpolation points N should therefore be chosen such that N / 2, N / 3,, N / n are integers, which can also be achieved approximately by interpolation (preferably trigonometric).
  • the demodulation method described with square-wave switching functions has the great advantage of simplicity, since it mainly requires addition and subtraction operations. It is therefore usually possible to use commercial array acquisition systems (eg diode array spectrometers, CCD methods, array detectors in X-ray diffractometers), as well as with, without additional device modification.
  • fast registering devices quadsi-array detection, for example conventional Fourier transform (FT) spectrometer, rapid-scan FT spectrometer and rapid-scan dispersion spectrometer
  • FT Fourier transform
  • a disadvantage of square wave demodulation is, however, that due to the odd overtones present in the switching function R (t) (see Eq. (6)), corresponding overtones of the signal ((2 ⁇ + l) ⁇ ), which are caused by the system's orharmonicity caused by anharmonic stimulation (see also MFS) are demodulated into the fundamental tone array A, ( ⁇ j- ⁇ p sD i).
  • this disadvantage is hardly significant if no exact analysis of the dynamics (kinetics) of the stimulated process is required, ie if an exact phase / amplitude frequency analysis does not have to be carried out. Because of the general importance and the simple feasibility, the demodulation of the fundamental tone of a periodic signal 28 (FIG. 4) will be discussed in more detail here.
  • the DC component 31 of the demodulated signal 32 becomes maximally positive if the freely selectable PSD phase angle ⁇ PSD, n> and the phase shift ⁇ n caused by the system dynamics are the same size, 30, FIG. 5A, ie ⁇ n - ⁇ PSD .
  • Modulation signals can therefore have a positive or negative sign. In addition, they can disappear completely at a phase difference of ⁇ 90 °.
  • the demodulated signal 41 assumes an intermediate amplitude A n 40, A n max > -A n > A n min .
  • the N support points (arrays) (Fig. 2B) are component by component with the harmonic switching function (7)
  • the multiplier (8) results for each component S kl of the interpolation point array S k
  • the averaging takes place analogously to the rectangular demodulation, with a harmonic factor of 2 having to be taken into account in the harmonic demodulation so that the signal amplitudes are transmitted 1: 1.
  • the overtones with the angular frequencies 2 ⁇ , 3 ⁇ ,, n ⁇ result analogously, the corresponding periods being ⁇ / 2, ⁇ / 3,, ⁇ / n and can therefore be evaluated 2, 3,, n times in the original data array.
  • the phase resolution is reduced accordingly.
  • the number of interpolation points N should therefore be chosen such that N / 2, N / 3,, N / n are integers, which is also approximate
  • Interpolation (preferably trigonometric) can be achieved.
  • FFT Fast Fourier Transformation
  • modified algorithms applied to the N reference point arrays of a wave train also lead to the desired results, namely DC term, fundamental and overtone arrays (FIG. IB), whereby, as in the PSD method, the maximum evaluable number of overtones is limited by the sampling theorem n ⁇ N / 2.
  • the disadvantage of the FFT compared to rectangular or harmonic demodulation is the greater computing effort and memory requirement; Boundary conditions that are not always met by commercial device computers.
  • Double stimulation of the system by simultaneous external change of any two parameters is considered as an example.
  • the different frequencies were used to differentiate the corresponding system responses used.
  • Parts of the system that only respond to parameter P 1 react with the frequency and their overtones, while those that only respond to P 2 have only the frequency ⁇ in the system response and their overtones.
  • System parts that respond to both parameters react as usual with double modulation with the sums and differences of the corresponding frequencies, namely: and the same applies to the overtones and to all other possible linear combinations of the two fundamental frequencies.
  • double demodulation with a switching function of the frequency ( ⁇ ⁇ and ⁇ 2 is required. 5.
  • the intensity spectra 27 (FIG. 4), which lie between an initial and end wave number, v lt and . v ⁇ , recorded in a time ⁇ s per scan and possibly accumulated M times, correspond to the support points (data arrays) according to FIGS. 2A and 2B.
  • the i-th component of the k-th support point can be described as follows:
  • the question generally arises as to the behavior of the concentrations of the reaction participants, ie according to the respective phase and amplitude, or. according to the Fourier coefficients used to describe the behavior over time.
  • the Lambert-Beer law (9) shows that the relationship between the measured quantity S ki and the concentration c k is not linear. If the concentration c (t) changes periodically due to external stimulation, S (t) is also a periodic function and can therefore be described with a Fourier series. The corresponding Fourierko ⁇ modified Bessel functions of entire order are effective. These can be calculated from the Fourier coefficients of c (t) using the Jacobi-Anger theorem (E. Jahnke and F. Emde, Tables of Functions with Formulae and Curves, Dover Publication
  • a kl is the i-th component of the k-th absorption support array. For the entire array, this results from GI. (11)
  • the array of DC components 44, a 0 is shown in FIG. 6, while the 17 (N + l) time-resolved absorption spectra a k mod are shown in FIG. 7.
  • the index k stands for the kth support point.
  • the spectrum 45 in FIG. 7 forms, for example, the 7th support point of the period.
  • the experimentally relevant equation (20) requires numerical integration, which, however, is generally based on elementary arithmetic operations. can be carried out with the standard software of commercial spectrometer computers without any problems.
  • the reference point arrays used for the PSD are shown in FIG. 7. They were calculated according to equation (20).
  • the signal arrays appearing in the output unit 20, FIG. 1B are determined as follows:
  • the DC term A Q results from averaging (eg through numerical integration and scaling) via the absorbance
  • the basic tone array Aj ( ⁇ , - ⁇ PSD, ⁇ ) is obtained by forming the
  • ⁇ PSD . I 22.5 ° results from analog processing of the support point arrays 2 to 10, respectively. 10 to 2 of FIG. 7.
  • the periodicity of the steady-state process has to be taken into account, i.e. as soon as a node number exceeds the value of N, subtract N from it.
  • the periodicity of the steady-state process must be taken into account, ie as soon as a node number exceeds N, the value N must be subtracted from it.
  • a k m ° d The modulated, time-dependent portion (FIG. 7, item 45) of the absorption support points of the sample was calculated in accordance with equation (20).
  • a Q The DC term of the absorption spectrum of the system response corresponds to a c (see above).
  • Aj phase-resolved fundamental spectra which correspond to the fundamental part of the modulated absorbance of the system response. They were determined by phase-sensitive detection at the fundamental tone frequency ⁇ using a square-wave switching function (6). See section 5.3. above.
  • a 2 Phase-resolved 1st harmonic spectra which correspond to the proportion of the first harmonic of the modulated absorbance of the system response. They were determined by phase-sensitive detection at the frequency 2 ⁇ (1st overtone) with a square-wave switching function (6). See section 5.3. above.
  • Fourier transform devices deliver interferograms as original data arrays S k . With a Fourier transformation, these must be converted into interpretable spectra.
  • the original data arrays are acquired as shown in FIG. 2A.
  • the interpolation point arrays S k of a period q are, however, not continuously accumulated, but are stored and demodulated after this period, ie during the period q + 1, according to one of the methods described in the two sections below.
  • the results A Q , A ⁇ , A 2 ,, A “are continuously accumulated, ie with the
  • the evaluation is carried out off-line by reading stored data from the buffer during data acquisition and storage and processing it using one of the demodulation methods described below.
  • a u A 2 ,, A. can be determined in two ways, but in which the original data must always be logarithmized:
  • the original data arrays are directly logarithmic and then fed to the PSD.
  • FIG. 11 shows a device for carrying out a temperature (T) modulation experiment.
  • An FTIR spectrometer or a diode array spectrometer serves as the analytical instrument (60).
  • the system (2) or the sample is located on both reflection surfaces of an ATR (attenuated total reflection) crystal, of which only half of the ATR plate (70) is shown.
  • the incident into the ATR plate (70) beam of light (71) originates from an interferometer (64) or diode array spectrometer ⁇ Spec. After one or more total reflections in the ATR plate (70), in which the system absorbs light a k (see equation (14)), the emerging light beam (72) is guided onto a detector (61) or detector array, in which the optical signal is converted into an electrical signal.
  • the analytical instrument (60) exists - in addition to the interferometer (64) or monochromator - from the detector (61) and a computer unit (65), which in turn from a data acquisition
  • the control and monitoring unit (63) is connected via lines (73) to the interferometer (64) or monochromator, via which all signals necessary for the operation of the analytical instrument are carried, e.g. those for controlling the mirror position of an interferometer.
  • the detector (61) is connected via lines (74) to the data acquisition (14) of the computer unit (65), via which the original data arrays S (t) are fed to the data acquisition (14).
  • a stimulation / reference unit (3) is provided for the external stimulation of the system (2), which is indicated by the arrow
  • the PSD (not shown), one of which maintains the circulating fluid at a temperature T and the other at a temperature T 2 .
  • the heat transfer to the system or to the cuvette takes place via a metallic heat exchanger plate, which is connected to the thermostats via hose connections.
  • the control of the reference / reference unit (3) takes place via lines (76) which connect the former to the computer unit (65).
  • the monochromator can be arranged in the beam path either in front of the system (2) or before the sample, or after the system (2) or after the sample .
  • FIG. 12 shows a device for carrying out an XRD X-ray diffraction-moisture (c) modulation experiment in a schematic representation.
  • the system (2) is a crystal and is located on a goniometer attachment (90).
  • An x-ray source (84 ') which is connected via line 86 to the control unit (84) of an x-ray diffractometer (80), is arranged to the system (2) in such a way that the x-ray (x-ray) (91) hits the crystal hits and creates a diffraction pattern.
  • the diffracted X-rays (92) hit a two-dimensional matrix detector (81) which is part of the X-ray diffractometer (80).
  • the crystal is influenced from the outside by a periodic change in a parameter, for example by changing the air humidity, which is done by the stimulation / reference unit (3) and is indicated schematically by the arrow (95).
  • This also modulates reflections from crystal regions that are influenced by the external modulation.
  • the signals which are time-resolved on the matrix detector (81) are fed to a simultaneous, digital PSD.
  • the remaining reference numerals in FIG. 12 correspond to those in FIG. 11 and have been described there.
  • Phase-resolved modulation data arrays are also the basic data for 2D correlation analyzes (2D spectroscopy). If the stimulated process runs too quickly to carry out a time-resolved acquisition of the original data arrays, the new method still provides very precise static information about the state of the system when one or off stimulation. This enables quasi-drift-free differential measurements, which has proven to be a significant advantage over previous methods. 8.2. Special applications
  • the task of optical spectroscopy includes the identification and the determination of the concentration and structure of chemical and biochemical substances. This also enables the determination of reaction schemes for processes that are triggered by a periodic, external stimulation.
  • the equilibrium of a chemical reaction can be influenced via the pressure p, provided the total volume of the reactants involved changes during the reaction.
  • a periodic p-modulation can therefore trigger periodic reactions, the maximum oscillation between the states caused by the lower, respectively. upper limit pressure are determined, p-modulation can e.g. to investigate reaction mechanisms of homogeneous and heterogeneous processes in the following areas:
  • Biotechnology interaction of gases with cell cultures and cell colonies.
  • the equilibrium of a chemical reaction can be influenced via the temperature T, provided that the reaction produces a heat (heat of reaction).
  • a periodic T modulation can therefore trigger periodic reactions, whose maximum oscillation between the states, which are determined by the lower, respectively. upper limit temperature are determined.
  • T-modulation can be used, for example, to investigate the reaction mechanisms of homogeneous and heterogeneous processes in the following areas:
  • Biotechnology growth dynamics of cell cultures and cell colonies.
  • Liquid-crystal (LC) technology analysis of phase changes and the interaction between LC and electrode.
  • the periodic change in the concentration of a reactant causes a periodic course of all reactions of the system in which the externally c-modulated reactant is involved.
  • the maximum concentration amplitudes of the reactants move between the equilibrium values that the upper, respectively. correspond to the lower concentration of the externally modulated reactant.
  • c-modulation can e.g. to investigate the reaction mechanisms of homogeneous and heterogeneous processes in the following areas:
  • Biotechnology interaction of active substances with cell cultures and cell colonies.
  • the equilibrium of chemical reactions can be influenced via the electric field, provided that a change in the state of charge and / or total dipole moment occurs between the educts and products during the reaction.
  • molecules with electrical charges and / or dipole moments can be aligned and / or shifted in the electrical field.
  • a periodic E-field modulation can therefore trigger or influence various types of periodic reactions. E-field modulation can e.g. to investigate the reaction mechanisms of homogeneous and heterogeneous processes in the following areas:
  • Liquid crystal (LC) technology Analysis of the dynamics of the LC reorientation in the E field, as well as the interaction between the LC and the electrode.
  • I-modulation plays a role in clarifying the mechanism of photochemical reactions, as well as in the development of photosensitive elements (e.g. detectors, information storage, energy storage).
  • photosensitive elements e.g. detectors, information storage, energy storage.
  • POL modulation plays a role in the dynamic and static investigation of molecular order states.
  • X-ray diffraction Modulated diffraction patterns (data arrays) of crystals can e.g. generated by T and c modulation. In the latter e.g. humidity can be modulated to investigate the influence of water of hydration on the molecular structure.
  • XPS X-Ray Photoelectron Spectroscopy
  • ESCA X-Ray Fluorescence Spectroscopy
  • XRF X-Ray Fluorescence Spectroscopy
  • the periodic system response can be modulated onto the radio frequency (RF) field when using a continuous wave (CW) NMR spectrometer.
  • RF radio frequency
  • CW continuous wave
  • Demodulation of the RF signal generates the modulated system response r, which can be subjected to a simultaneous, digital PSD.
  • ESR Electron spin resonance spectroscopy
  • the periodic system response can be modulated onto the ESR signal ( ⁇ 100 kHz) by modulating external parameters.
  • the demodulation of this signal generates the modulated system response, which can be subjected to a simultaneous, digital PSD.
  • the modulation of external parameters can be used to modulate the quadrupole splitting, for example of iron in hamoglo am to generate in Mössbauer spectra (data arrays).

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)

Abstract

Ce procédé de mesure et d'analyse permet de déterminer par détection sensible aux phases la réponse d'un système susceptible d'être stimulé périodiquement. A cet effet, un paramètre thermodynamique externe est périodiquement modifié. On peut utiliser des séries de données au lieu des valeurs de mesures scalaires normalement utilisées dans l'état antérieur aussi bien pour saisir des données que pour les traiter. Pendant la saisie des données, la période est subdivisée en un nombre déterminé de points d'appui qui représentent chacun un vecteur de données à un moment donné à l'intérieur de cette période. L'enregistrement numérique des points d'appui d'au moins une période suit la détection simultanée sensible aux phases. En traitant simultanément les données de mesure, on réussit à réduire dans le temps le nombre de composants de la série de données en conservant le même rapport signal/bruit. Un élément essentiel de la caractérisation des qualités cinétiques du processus stimulé est la série d'angles de phases qui reproduit le retardement de la réponse du système par rapport à la stimulation composant par composant. L'invention concerne des dispositifs d'expérimentation par modulation et par diffraction d'infrarouges et de rayons X à transformation de Fourrier. Ce procédé trouve des applications en spectroscopie optique, dans des procédés de diffraction, en traitement d'images, et de manière générale dans des techniques de mesure au moyen de détecteurs agencés en rangées unidimensionnelles ou bidimensionnelles, ou par saisie sérielle rapide (presque simultanée) de données.
PCT/CH1996/000293 1995-08-25 1996-08-26 Procede de detection numerique simultanee sensible aux phases de series de donnees saisies pratiquement en meme temps, resolues dans le temps et faisant partie d'un systeme periodiquement stimule WO1997008598A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH242995 1995-08-25
CH2429/95-4 1995-08-25

Publications (1)

Publication Number Publication Date
WO1997008598A1 true WO1997008598A1 (fr) 1997-03-06

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PCT/CH1996/000293 WO1997008598A1 (fr) 1995-08-25 1996-08-26 Procede de detection numerique simultanee sensible aux phases de series de donnees saisies pratiquement en meme temps, resolues dans le temps et faisant partie d'un systeme periodiquement stimule

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10864235B2 (en) 2012-11-23 2020-12-15 Seres Therapeutics, Inc. Synergistic bacterial compositions and methods of production and use thereof
US11185562B2 (en) 2013-02-04 2021-11-30 Seres Therapeutics, Inc. Compositions and methods for inhibition of pathogenic bacterial growth
US11266699B2 (en) 2013-11-25 2022-03-08 Seres Therapeutics, Inc. Synergistic bacterial compositions and methods of production and use thereof
US11701394B2 (en) 2017-08-14 2023-07-18 Seres Therapeutics, Inc. Compositions and methods for treating cholestatic disease
CN117518939A (zh) * 2023-12-06 2024-02-06 广州市顺风船舶服务有限公司 一种基于大数据的工业控制系统
US12083151B2 (en) 2012-11-23 2024-09-10 Seres Therapeutics, Inc. Synergistic bacterial compositions and methods of production and use thereof

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US5175698A (en) * 1990-07-23 1992-12-29 Dz Company Method and system for transfer function measurement
EP0558179A2 (fr) * 1992-02-28 1993-09-01 Hewlett-Packard Company Déterminer la réponse d'une boucle d'asservissement ouverte en vertu de mesures sur un circuit de réglage bouclé
WO1994017762A1 (fr) * 1993-02-10 1994-08-18 Noise Cancellation Technologies, Inc. Procede perfectionne d'identification directe de systeme
GB2279777A (en) * 1993-06-30 1995-01-11 West Instr Limited Self tuning process control system

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5175698A (en) * 1990-07-23 1992-12-29 Dz Company Method and system for transfer function measurement
EP0558179A2 (fr) * 1992-02-28 1993-09-01 Hewlett-Packard Company Déterminer la réponse d'une boucle d'asservissement ouverte en vertu de mesures sur un circuit de réglage bouclé
WO1994017762A1 (fr) * 1993-02-10 1994-08-18 Noise Cancellation Technologies, Inc. Procede perfectionne d'identification directe de systeme
GB2279777A (en) * 1993-06-30 1995-01-11 West Instr Limited Self tuning process control system

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10864235B2 (en) 2012-11-23 2020-12-15 Seres Therapeutics, Inc. Synergistic bacterial compositions and methods of production and use thereof
US11389490B2 (en) 2012-11-23 2022-07-19 Seres Therapeutics, Inc. Synergistic bacterial compositions and methods of production and use thereof
US11458174B2 (en) 2012-11-23 2022-10-04 Seres Therapeutics, Inc. Synergistic bacterial compositions and methods of production and use thereof
US11458173B2 (en) 2012-11-23 2022-10-04 Seres Therapeutics, Inc. Synergistic bacterial compositions and methods of production and use thereof
US11464812B2 (en) 2012-11-23 2022-10-11 Seres Therapeutics, Inc. Synergistic bacterial compositions and methods of production and use thereof
US12083151B2 (en) 2012-11-23 2024-09-10 Seres Therapeutics, Inc. Synergistic bacterial compositions and methods of production and use thereof
US11185562B2 (en) 2013-02-04 2021-11-30 Seres Therapeutics, Inc. Compositions and methods for inhibition of pathogenic bacterial growth
US11266699B2 (en) 2013-11-25 2022-03-08 Seres Therapeutics, Inc. Synergistic bacterial compositions and methods of production and use thereof
US11918612B2 (en) 2013-11-25 2024-03-05 Seres Therapeutics, Inc. Synergistic bacterial compositions and methods of production and use thereof
US11701394B2 (en) 2017-08-14 2023-07-18 Seres Therapeutics, Inc. Compositions and methods for treating cholestatic disease
CN117518939A (zh) * 2023-12-06 2024-02-06 广州市顺风船舶服务有限公司 一种基于大数据的工业控制系统

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